Such a pedestrian warning device is disclosed in the German patent specification, DE 3408270 which discloses a system wherein a brake signal lamp at the front of the vehicle is lightened up when the rear brake lamp is illuminated. One drawback of the pedestrian warning device according to DE 3408270 is that the lamp will be illuminated as soon as the brake pedal is pressed down. So, if the driver just leans the foot on the brake pedal the lamp could be illuminated.
U.S. 2008094254, WO0213162 and WO 2008156378 and normally detects that a pedestrian is intended to cross the road or detects that the road signal is going to be red thereby warning the driver before a cross road point. These devices also warn the pedestrian and emit an acoustic signal when the pedestrian is in front of the vehicle. A drawback with such a device is that the device will emit an acoustic signal every time the vehicle approaches another vehicle in a traffic jam.
In U.S. Pat. No. 5,025,245 a pedestrian signal system for automobiles is disclosed. This system functions in such a way that the driver can push a button to actuate the system and by thereafter pressing the brake pedal flashing means actuate the turn lights of the pedestrian signal system. The system is actuated by the driver by pushing a button which is an unreliable way of operation.